Refusing one meal won't stunt your growth. But lack of proper food over a period of time can lead to malnutrition. That means, the body is not getting enough nutrients to grow and stay healthy. Kids who are malnourished may not grow as tall as they would otherwise.

Why We Need Food

Did you ever hear the old saying,
An apple a day keeps the doctor away
? Do apples really prevent you from getting sick? Probably not, but eating apples and other fresh fruits can help keep you healthy. Do you eat your vegetables? Maybe you do, but you may have friends who won't touch a piece of broccoli or asparagus. Should you eat these foods and food like them? The girls pictured below are eating salads (
Figure
below
). Why do you need foods like these for good health? What role does food play in the body?

These girls are eating leafy green vegetables. Fresh vegetables such as these are excellent food choices for good health.

Your body needs food for three reasons:

Food gives your body energy. You need energy for everything you do. Remember that
cellular respiration
converts the glucose in the food you eat into
ATP
, or cellular energy. Which has more glucose, a salad or a piece of meat? Do you remember what types of foods produce glucose? Recall that glucose is the product of photosynthesis.

Food provides building materials for your body. Your body needs building materials so it can grow and repair itself. Specifically, it needs these materials to produce more cells and its components.

Food contains substances that help control body processes. Your body processes must be kept in balance for good health.

For all these reasons, you must have a regular supply of nutrients.
Nutrients
are chemicals in food that your body needs. There are five types of nutrients:

Carbohydrates
.

Proteins
.

Lipids
.

Vitamins
.

Minerals
.

Carbohydrates, proteins, and lipids are categories of organic compounds. They give your body energy, though carbohydrates are the main source of energy. Proteins provide building materials, such as amino acids to build your own proteins. Proteins, vitamins, and minerals also help control body processes. Carbohydrates include sugars such as the glucose made by photosynthesis. Often glucose is stored in large molecules such as starch. Proteins are found in foods like meats and nuts. Lipids includes fats and oils. Though you should stay away from many types of fats, others are needed by your body. Important vitamins include vitamins A, B (multiple types) C, D, and E. Important minerals include calcium and potassium. What should you drink to get calcium? Milk is a good source.

Vocabulary

ATP (adenosine triphosphate)
: Usable form of energy inside the cell; the "energy currency" of the cell.

carbohydrate
: Organic compound such as sugar and starch that provides an energy source for animals.

cellular respiration
: Process of breaking down glucose to obtain energy in the form of ATP.

lipid
: Organic compound that is insoluble in water and includes fats, oils, and waxes.

mineral
: Chemical element, such as calcium or potassium that is needed for body processes.